Children as young as 12 have been treated for the effects of taking drugs, a north Belfast doctor has revealed.
Dean Clarke died a week after being found on the Limestone Road
Dr Sean Donnelly said the drugs ecstasy and diazepam were easily available on the streets.
His comments came as thousands of mourners attended the funeral of teenager Dean Clarke.
The 16-year-old from the Tigers Bay area of north Belfast killed himself after overdosing on drugs.
He had spent almost a week in intensive care after taking ketamine tablets, which are used as horse tranquilisers, prior to his death.
Dr Donnelly said the youngest child he had treated for the effects of drugs was 12, although he had heard of even younger children being involved.
Dean Clarke's family blamed a UDA drug dealer for his death.
Mourners included nationalist and unionist politicians as well as the UPRG's Frankie Gallagher.
Thousands of mourners attended Dean Clarke's funeral
Pastor Brian Madden, who officiated at the funeral, earlier this week claimed drugs were easy to acquire in the area. He said ketamine could be bought for 50p.
"While people may be in denial that drugs existed, while people may be in denial that drugs are not being peddled, I always knew that to be completely opposite to the truth," he said.
"I know people personally who are addicted to cocaine, I know people personally who are addicted to tranquilisers."